Various forms of lighted nocks, or crossbow bolt ends (as the functionally equivalent device is known when utilizing a crossbow) are known in the art, but all suffer from certain drawbacks. Although arrow nocks and crossbow bolt ends are distinguished in their general shape, both are collectively referred to herein as a “nock” for convenience of description.
A lighted arrow nock allows an archer to be able to more easily see the arrow in flight, see the point of arrow impact, and recover the arrow after a shot. Being able to observe the arrow in flight and see the point of impact helps the archer to diagnose problems with shooting form or bow setup and make appropriate adjustments. Perhaps more importantly, a lighted arrow nock allows an archer to more easily recover the arrow.
Bow hunters can especially benefit from using an arrow with a lighted nock device. Recovering an arrow that was shot at an animal is critical in the ethical harvest of animals, and a lighted nock device allows a bow hunter to recover the arrow and animal more easily. Upon recovering the arrow, the bow hunter can diagnose many things about the shot by inspecting the arrow. The presence of blood or other debris on the arrow, or lack thereof, gives many clues as to if the arrow impacted the animal in a desired vital area or not, or if the arrow even hit the animal at all.
Some previous lighted nock designs have utilized a chemical light source or have been composed of luminescence material, such as U.S. Pat. No. 4,856,792, issued Aug. 15, 1989 to Philip M. Hardison; U.S. Pat. No. 6,364,499, issued Apr. 2, 2002 to Thomas M. Jones; and U.S. Pat. No. 7,211,011 issued May 1, 2007 to Warren Sutherland. To activate the chemical light source, a vial or container must be broken to allow the mixing of chemicals to produce a light emitting chemical reaction. The nock or vial cannot be turned off and must be disposed of because it had to be broken to allow the chemicals to mix. The largest drawback to these designs is the amount of light emitted from these chemical sources is not bright enough to be effective. Additionally, these designs add weight and cost to the arrow but do not provide enough light to see the arrow in flight or to see the point of arrow impact. The Hardison and Sutherland devices require the vial to be broken before the bow is shot, either before the nock is assembled to the arrow or when the nock is placed onto the bowstring. A bow hunter needs to hunt prepared to release an arrow at an animal with little notice. To be prepared for a quick shot, the hunter should break these vials every time they hunt, but often bow hunters never get an opportunity to shoot while hunting so these broken vials go to waste. If the hunter tries to conserve the nock or vial by waiting to break the vial until they see an animal they want to shoot, then they risk alerting the animal with too much noise or movement or taking too much time installing it and thus losing the shot opportunity. Whichever method the hunter tried to activate, because they must be activated prior to the shot, it is possible for the animal to see the light coming from the device and spot the hunter before the hunter can draw and shoot the bow and arrow. The Jones device allows for breaking of the vial during the shot and not prior to the shot, but still suffers from not being able to be turned off when desired and the amount of light is not generally sufficient to see the arrow in flight, the point of arrow impact, or to assist in recovering the arrow.
Some lighted nock designs have embedded battery powered lamps or light emitting diodes (LEDs). For example, U.S. Pat. No. 6,123,631, issued on Sep. 26, 2000 to Jeffery Allen Ginder, utilizes a battery-powered light emitting diode (LED). This lighted nock device is always turned on unless it is nocked on the bowstring or unless a special cap is attached to the nock to turn off the LED. The switch used in the Ginder device is a non-latching switch that is always in the closed or “on” position and either the bowstring or the special cap opens the switch to turn off the LED. The cap can easily become lost and quickly drain the battery rendering the nock useless. The cap is extra weight to carry on the arrows in your quiver and extra hassle to worry about. When removing the cap, the switch will close and turn on the LED before it is ever mounted on the bow where the bowstring opens the switch and turns off the LED again. This may be acceptable for target archers, but for bow hunters this is not desirable as an animal could be alerted by the light coming from the device and spot the hunter. If a bow hunter needed to make a quick second shot he would have to remove the cap from his second arrow before being able to install the second arrow which would waste time. After the arrow is shot and the arrow strikes an animal or the ground, the LED could easily be turned off if animal tissue, leaves, or any other debris becomes lodged in the nock, thus opening the switch.
U.S. Pat. No. 6,390,642, issued on May 21, 2002 to Robert Wayne Simonton, also utilizes a battery powered LED and has a switch that is responsive to a magnetic field. This design requires a separate magnet to be attached to the bow which not only adds cost and weight, but the magnet can also be lost in the field rendering the lighted nock device useless. The system also requires a printed circuit board to house the electronics to sense the magnetic field and switch the LED on or off. The circuit must remain on which can drain the battery when not in use. The required electronics add unnecessary weight to the arrow and drive up the cost of the device.
U.S. Pat. No. 6,736,742, issued on May 18, 2004 to Curtis Lee Price and Ivan Eric Price, also uses a battery powered LED, but its switching mechanism requires critical contact with the arrow shaft to activate the LED which can lead to a lack of reliability. The nock of the Price device has two metal contact points that are forced into the rear of the arrow shaft during the release of the bow. The arrow shaft requires special preparation to ensure that metal contacts touch the shaft correctly, which is often done improperly or completely overlooked by archers resulting in unreliable activation. The Price device also requires the arrow to be electrically conductive and thus will not work with fiberglass, wood, or other nonconductive arrow materials. The largest drawback to the Price design is that often the lighted nock will turn off upon impact due to vibrations from the impact causing the metal contacts to lose contact with the rear of the arrow. Because the nock must slide in and out to turn on and off, respectively, the nock and the arrow wear on each other and become loose over time, compounding the problem of the device turning off inadvertently during impact. As the metal contacts are repeatedly forced into the arrow shaft, the arrow shaft is gouged by the metal contacts, creating a problem for the critical electrical contact between the metal contacts and the arrow shaft.
U.S. Pat. No. 7,021,784, issued Apr. 4, 2006 to Joseph L. DiCarlo, is another lighted nock device which uses battery powered LEDs. This device also requires the nock to slide back and forth in the arrow against a special backstop, which must be installed in the arrow before the lighted nock device can be used. The archer must glue the backstop into the rear of his arrow at a precise depth or the LED will not activate correctly. The backstop and the glue add unnecessary weight to the arrow. Because the nock must slide in and out of the arrow to be turned on and to be turned off, respectively, the nock and the arrow wear on each other and become loose over time.
What is needed is an illuminated arrow nock that will turn on upon release of a bowstring, is more dependable, and does not require any extra parts, assembly, or preparation work by the archer.